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| United States Patent |
6,129,199
|
|
Gretener
, et al.
|
October 10, 2000
|
Method and device for channeling parceled goods
Abstract
Process and apparatus for controlling the channeling of parceled goods to
be delivered via a delivery conveyor, which includes at least one buffer
conveyor, a call-up conveyor, and a channeling conveyor, to free locations
on an acceptance conveyor running at a constant speed. The acceptance
conveyor and the delivery conveyor are arranged to encompass an angle
.alpha., and the delivery conveyor is provided with a parcel measuring
device. The process includes measuring a length of a parcel to be
channeled, determining a length of time t2 utilized in measuring the
length of the parcel, and determining a momentary parcel speed; a speed of
the channeling conveyor to which the parcel will be transferred; a
distance on the call-up conveyor on which acceleration of the parcel
occurs prior to a transfer of the parcel to the channeling conveyor; and a
position of a next free space on the acceptance conveyor. The process also
includes synchronizing movement of the parcel to the next free space by
one of (a) accelerating and decelerating and (b) decelerating and
accelerating the parcel on the call-up conveyor at a constant acceleration
a, and without intermediate stopping of the call-up conveyor, transferring
the parcel from the call-up conveyor to the channeling conveyor, and
synchronously transferring the parcel to the next free space on the
acceptance conveyor. The apparatus includes a measuring device to measure
a length of a parcel to be transferred from the delivery conveyor to the
acceptance conveyor, wherein the measurement of the length occurs in a
time t2, a control device provided for determining a momentary speed of
parcel; a speed of the channeling conveyor to which the parcel will be
transferred; a distance on the call-up conveyor on which acceleration of
the parcel occurs prior to a transfer to the channeling conveyor; and a
position of a next empty space on the acceptance conveyor. The control
device also is provided to adjust one of (a) an acceleration and
deceleration and (b) a deceleration and acceleration of the parcel on the
call-up conveyor, without intermediate stopping of the call-up conveyor,
to synchronize the movement of the parcel to the next empty space on the
acceptance conveyor.
| Inventors:
|
Gretener; Urs (Ennetturgi, CH);
Heinz; Bear (Sils i.D., CH);
Rykart; Ruedi (Schmidrued, CH)
|
| Assignee:
|
Siemens Schweiz AG (Zurich, CH);
Grapha-Holdings AG (Hergiswil, CH)
|
| Appl. No.:
|
817827 |
| Filed:
|
June 26, 1997 |
| PCT Filed:
|
September 5, 1996
|
| PCT NO:
|
PCT/CH96/00305
|
| 371 Date:
|
June 26, 1997
|
| 102(e) Date:
|
June 26, 1997
|
| PCT PUB.NO.:
|
WO97/09256 |
| PCT PUB. Date:
|
March 13, 1997 |
Foreign Application Priority Data
| Sep 08, 1995[CH] | 2560/95-2 |
| Current U.S. Class: |
198/357; 198/370.04; 198/502.2 |
| Intern'l Class: |
B65G 047/46 |
| Field of Search: |
198/370.3-370.6,357,460.1,502.2
|
References Cited
U.S. Patent Documents
| 3747781 | Jul., 1973 | Daigle et al. | 198/357.
|
| 3817368 | Jun., 1974 | Wentz et al. | 198/357.
|
| 4915209 | Apr., 1990 | Canziani | 198/357.
|
| 5267638 | Dec., 1993 | Doane.
| |
| 5341916 | Aug., 1994 | Doane et al.
| |
| 5860504 | Jan., 1999 | Lazzarotti | 198/357.
|
| Foreign Patent Documents |
| 0305755 | Mar., 1989 | EP.
| |
| 0343613 | Aug., 1992 | EP.
| |
| 0527542 | Feb., 1993 | EP.
| |
| 0577021 | Jan., 1994 | EP.
| |
| 0619248 | Oct., 1994 | EP.
| |
Primary Examiner: Valenza; Joseph E.
Attorney, Agent or Firm: Greenblum & Bernstein, P.L.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a U.S. National Stage of International
Application No. PCT/CH96/00305 filed Sep. 5, 1996 and claims priority
under 35 U.S.C. .sctn. 119 of Swiss Patent Application No. 2560/95-2,
filed on Sep. 8, 1995.
Claims
What is claimed is:
1. A process for controlling a channeling of parceled goods, comprising:
disposing a parcel acceptance conveyor along a first path, said parcel
acceptance conveyor moving at a given speed;
communicating the given speed of the acceptance conveyor to a control unit;
determining the position of a free space which will receive the parcel and
communicating the position to the control unit;
conveying a parcel along a second path, the second path intersecting the
first path at an angle, the conveying taking place by way of a delivery
conveyor which moves the parcel to a first transfer point, at least one
call-up conveyor which further moves the parcel to a second transfer
point, and a channeling conveyor which moves the parcel to the parcel
acceptance conveyor;
determining the position of the parcel which has stopped on the delivery
conveyor and communicating the position to a control unit;
determining a speed of the at least one call-up conveyor and communicating
the speed to the control unit;
measuring a length of a parcel to be channeled as the parcel is moved on
the at least one call-up conveyor and communicating the length to the
control unit;
determining a length of time t2 utilized in measuring the length of the
parcel with the control unit;
determining a speed of the channeling conveyor to which the parcel will be
transferred and communicating the speed to the control unit;
calculating the acceleration and deceleration gradient for the at least one
call-up conveyor prior to a transfer of the parcel to the channeling
conveyor with the control unit;
synchronizing a movement of the parcel to the free space by controlling the
previously calculated acceleration and deceleration gradient of the at
least one call-up conveyor carrying the parcel with the control unit;
transferring the parcel from the at least one call-up conveyor to the
channeling conveyor which is moving at a constant speed, the transferring
occurring at the speed of the channeling conveyor; and
synchronously transferring the parcel to the free space on the acceptance
conveyor.
2. The process of claim 1, further comprising:
determining the distance on the at least one call-up conveyor on which the
parcel can be accelerated prior to transfer to the channeling conveyor,
the determining being based upon the measured length of the parcel, a
total length of the at least one call-up conveyor, and at least
approximately a distance which the parcel has traveled on the at least one
call-up conveyor during time t2.
3. The process of claim 1, further comprising:
conveying a plurality of containers or tipping trays for receiving the
parcel on the acceptance conveyor,
wherein the synchronous movement of the parcel is synchronized with a front
edge of a next empty container or tipping tray, and
wherein, when a synchronization time is insufficient to synchronize the
movement of the parcel to the front edge of the next empty container or
tipping tray, the synchronous movement of the parcel is synchronized with
a rear edge of the next empty container or tipping tray.
4. The process of claim 3, wherein, when a synchronization time is
insufficient to synchronize the movement of the parcel to the next empty
container or tipping tray, the synchronous movement of the parcel is
synchronized with a subsequent empty container or tipping tray positioned
upstream, relative to an acceptance conveyor direction, from the next
empty container or tipping tray.
5. The process of claim 1, further comprising:
performing a synchronization calculation not later than at time t2, at
which time the parcel has passed through a light barrier, the light
barrier being one of:
positioned at a beginning of the at least one call-up conveyor and arranged
perpendicularly to the acceptance conveyor; and
positioned at a beginning of the at least one call-up conveyor and arranged
perpendicularly to the delivery conveyor;
measuring a lateral deviation of the parcel; and
including a corresponding delay in the synchronization calculation in
accordance with the measured lateral deviation.
6. The process according to claim 1, wherein the measuring of the length of
the parcel is performed by a control device having a counting device and
one of a light barrier arranged perpendicularly to the acceptance conveyor
and a light barrier arranged perpendicular to the buffer conveyor.
7. The process according to claim 1, further comprising:
balancing the process with a cycle of the acceptance conveyor and a unit
interval per cycle of the acceptance conveyor.
8. The process of claim 1, wherein the parcel acceptance conveyor is moving
at a constant speed.
9. The process of claim 1, further comprising:
accelerating the parcel on the delivery conveyor to the speed of the at
least one call-up conveyor, via control signals from the control unit to
the delivery conveyor, prior to transferring the parcel to the at least
one call-up conveyor.
10. The process of claim 9, wherein the accelerating occurs after the
determining a speed of the at least one call-up conveyor.
11. The process of claim 9, wherein the accelerating comprises accelerating
the parcel on the delivery conveyor with nearly constant acceleration and
deceleration to the speed of the at least one call-up conveyor.
12. The process of claim 1, wherein the parcel is in continuous motion from
the point where it enters the at least one call-up conveyor to the point
where it is loaded onto the free space.
13. A process for controlling a channeling of parceled goods, comprising:
disposing a parcel acceptance conveyor along a first path, said parcel
acceptance conveyor moving at a constant speed;
communicating the speed of the acceptance conveyor to a control unit;
determining the position of an empty tipping tray which will receive the
parcel and communicating the position to the control unit;
conveying a parcel along a second path, the second path intersecting the
first path at an angle, the conveying taking place by way of a delivery
conveyor which moves the parcel to a first transfer point, at least one
call-up conveyor which further moves the parcel to a second transfer
point, and a channeling conveyor which moves the parcel to the parcel
acceptance conveyor;
determining the position of the parcel which has stopped on the delivery
conveyor and communicating the position to a control unit;
determining a speed of the at least one call-up conveyor and communicating
the speed to the control unit;
accelerating the parcel on the delivery conveyor to the speed of the at
least one call-up conveyor, via control signals from the control unit to
the delivery conveyor, prior to transferring the parcel to the call-up
conveyor;
measuring a length of a parcel to be channeled as the parcel is moved on
the at least one call-up conveyor and communicating the length to the
control unit;
determining a length of time t2 utilized in measuring the length of the
parcel with the control unit;
determining a speed of the channeling conveyor to which the parcel will be
transferred and communicating the speed to the control unit;
calculating the acceleration and deceleration gradient for the at least one
call-up conveyor prior to a transfer of the parcel to the channeling
conveyor with the control unit;
synchronizing a movement of the parcel to the empty tipping tray by
controlling the previously calculated acceleration and deceleration
gradient of the at least one call-up conveyor carrying the parcel with the
control unit;
transferring the parcel from the at least one call-up conveyor to the
channeling conveyor which is moving at a constant speed, the transferring
occurring at the speed of the channeling conveyor; and
synchronously transferring the parcel to the empty tipping tray on the
acceptance conveyor,
wherein the parcel is in continuous motion from the point where it enters
the call-up conveyor to the point where it is loaded onto the tipping
tray.
14. The apparatus of claim 13, wherein the calculating comprises
calculating how much to constantly accelerate and constantly decelerate
the at least one call-up conveyor prior to a transfer of the parcel to the
channeling conveyor with the control unit.
15. A process for controlling a channeling of parceled goods, comprising:
disposing a parcel acceptance conveyor along a first path, said parcel
acceptance conveyor moving at a constant speed;
communicating the speed of the acceptance conveyor to a control unit;
determining the position of a free space which will receive the parcel and
communicating the position to the control unit;
conveying a parcel along a second path, the second path intersecting the
first path at an angle, the conveying taking place by way of a delivery
conveyor which moves the parcel to a first transfer point, at least one
call-up conveyor which further moves the parcel to a second transfer
point, and a channeling conveyor which moves the parcel to the parcel
acceptance conveyor;
determining the position of the parcel which has stopped on the delivery
conveyor and communicating the position to a control unit;
determining a speed of the at least one call-up conveyor and communicating
the speed to the control unit;
accelerating the parcel on the delivery conveyor to the speed of the at
least one call-up conveyor, via control signals from the control unit to
the delivery conveyor, prior to transferring the parcel to the at least
one call-up conveyor;
measuring a length of a parcel to be channeled as the parcel is moved on
the at least one call-up conveyor and communicating the length to the
control unit;
determining a length of time t2 utilized in measuring the length of the
parcel with the control unit;
determining a speed of the channeling conveyor to which the parcel will be
transferred and communicating the speed to the control unit;
calculating the acceleration and deceleration gradient for the at least one
call-up conveyor prior to a transfer of the parcel to the channeling
conveyor with the control unit;
synchronizing a movement of the parcel to the free space by controlling the
previously calculated acceleration and deceleration gradient of the at
least one call-up conveyor carrying the parcel with the control unit;
transferring the parcel from the at least one call-up conveyor to the
channeling conveyor which is moving at a constant speed, the transferring
occurring at the speed of the channeling conveyor; and
synchronously transferring the parcel to the free space on the acceptance
conveyor,
wherein the parcel is in continuous motion from the point where it enters
the at least one call-up conveyor to the point where it is loaded onto the
free space.
16. The apparatus of claim 15, wherein the calculating comprises
calculating how much to constantly accelerate and constantly decelerate
the at least one call-up conveyor prior to a transfer of the parcel to the
channeling conveyor with the control unit.
17. An apparatus for controlling a channeling of parceled goods,
comprising:
a parcel acceptance conveyor disposed along a first path, said parcel
acceptance conveyor moving at a speed, the speed of the acceptance
conveyor being communicated to a control unit;
the apparatus determining a position of the free space which will receive
the parcel and communicating the position to the control unit;
a second path for conveying a parcel, the second path intersecting the
first path at an angle, the conveying taking place by way of a delivery
conveyor which moves the parcel to a first transfer point, at least one
call-up conveyor which further moves the parcel to a second transfer
point, and a channeling conveyor which moves the parcel to the parcel
acceptance conveyor;
a device for determining the position of the parcel which has stopped on
the delivery conveyor and communicating the position to the control unit;
a device for determining a speed of the at least one call-up conveyor and
communicating the speed to the control unit;
a device for measuring a length of a parcel to be channeled as the parcel
is moved on the at least one call-up conveyor and communicating the length
to the control unit, a length of time t2 utilized in measuring the length
of the parcel being determined with the control unit;
a device for determining a speed of the channeling conveyor to which the
parcel will be transferred and communicating the speed to the control
unit;
the control unit calculating the acceleration and deceleration gradient for
the at least one call-up conveyor prior to a transfer of the parcel to the
channeling conveyor; and
the control unit synchronizing a movement of the parcel to the free space
by controlling the previously calculated acceleration and deceleration of
the at least one call-up conveyor carrying the parcel,
wherein the parcel is transferred from the at least one call-up conveyor to
the channeling conveyor which is moving at a constant speed, the
transferring occurring at the speed of the channeling conveyor; and
wherein the parcel is synchronously transferred to the free space on the
acceptance conveyor.
18. The apparatus of claim 17, further comprising:
a first light barrier arranged perpendicularly to the buffer conveyor; and
a second light barrier arranged perpendicularly to the acceptance conveyor;
wherein one of the first and the second light barrier is utilized to
measure the length of the parcel, and wherein the second light barrier is
utilized for determining the time t2 at which the synchronization process
begins.
19. The apparatus of claim 17, further comprising:
a first light barrier arranged perpendicularly to the buffer conveyor;
a second light barrier arranged perpendicularly to the delivery conveyor;
and
a device for measuring a lateral deviation of the parcel on the delivery
conveyor,
wherein the control device includes a device for causing a delay
corresponding to the lateral deviation of the parcel on the delivery
conveyor when calculating the synchronization process.
20. The apparatus of claim 17, wherein the control unit is adapted to
control the call-up conveyor and the buffer conveyor.
21. The apparatus of claim 17, wherein the at least one call-up conveyor
comprises two separate controllable call-up conveyors with light barriers
being located at the ends of the two separate controllable call-up
conveyors which are coupled to the control unit.
22. The apparatus of claim 17, wherein the acceptance conveyor comprises at
least one container or tipping tray disposed thereon for accepting the
parcel to be transferred from the delivery conveyor,
wherein a front edge of a next container or tipping tray is a target of the
synchronized movement of the parcel, and
wherein, when insufficient time remains to synchronize the movement of the
parcel to the front edge of the next container or tipping tray, one of the
rear end and the center of the next container or tipping tray is the
target of the synchronized movement of the parcel.
23. The apparatus of claim 17, further comprising:
a device for determining the distance on the at least one call-up conveyor
on which the parcel can be accelerated prior to transfer to the channeling
conveyor, the determining being based upon the measured length of the
parcel, a total length of the at least one call-up conveyor, and at least
approximately a distance which the parcel has traveled on the at least one
call-up conveyor during time t2.
24. The apparatus of claim 17, wherein the control unit performs a
synchronization calculation not later than at time t2, at which time the
parcel has passed through a light barrier, the light barrier being one of:
positioned at a beginning of the at least one call-up conveyor and arranged
perpendicularly to the acceptance conveyor; and
positioned at a beginning of the at least one call-up conveyor and arranged
perpendicularly to the delivery conveyor;
measuring a lateral deviation of the parcel; and
including a corresponding delay in the synchronization calculation in
accordance with the measured lateral deviation.
25. The apparatus of claim 17, wherein the parcel acceptance conveyor is
moving at a constant speed.
26. The apparatus of claim 17, wherein the control unit is adapted to
accelerate the parcel on the delivery conveyor to the speed of the at
least one call-up conveyor, via control signals from the control unit to
the delivery conveyor, prior to transferring the parcel to the at least
one call-up conveyor.
27. The apparatus of claim 26, wherein the accelerating occurs after the
determining a speed of the at least one call-up conveyor.
28. The apparatus of claim 26, wherein the accelerating comprises
accelerating the parcel on the delivery conveyor with nearly constant
acceleration and deceleration to the speed of the at least one call-up
conveyor.
29. The apparatus of claim 17, wherein the parcel is in continuous motion
from the point where it enters the at least one call-up conveyor to the
point where it is loaded onto the free space.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process and apparatus for controlling
the channeling of parceled goods to be delivered via a delivery conveyor,
which includes at least one buffer conveyor, a call-up conveyor, and a
channeling conveyor, to free locations on an acceptance conveyor running
at a constant speed. The acceptance conveyor and the delivery conveyor are
arranged to encompass an angle .alpha., and the delivery conveyor is
provided with a parcel measuring device.
2. Discussion of Background Information
For sorting parceled goods, e.g., for parcel shipments in postal
operations, sorting units are used which, for example, are known from EP A
0 305 755, EP A 0 343 613 or EP A 0 619 248. Sorting units of this type,
which allow an almost fully automated distribution of incoming parceled
goods to various users, are provided with at least with one acceptance
conveyor on which the parceled goods to be distributed are placed of at
least one channeling device which has at least one delivery conveyor. The
parceled goods provided to the target addresses are conveyed on the
acceptance conveyor to a channeling device consistent with the target
address of the parceled goods. By channeling the parceled goods to its
destination, the conveyor is vacated for reloading with parceled goods by
means of the channeling device. Due to the steady increase in the flow of
parceled goods in the cargo area and the high investment costs involved in
sorting facilities, efforts are made to achieve a high processing volume
of parceled goods in these installations. Achieving a high processing
volume of parceled goods is primarily contingent upon a exact positioning
of individual parcels on the acceptance conveyor. If the parceled goods
are not placed precisely on the acceptance conveyor by the channeling
device, this can result in malfunctions which always must be remedied by
manual intervention. The devices used for channeling parceled goods of
varying size, shape and weight also must meet special requirements, so
that the parceled goods are positioned exactly on the acceptance conveyor.
This applies, in particular, when operating tipping tray installations in
which the parceled goods to be channeled are placed on tipping trays. EP A
0 305 755 already determined that parceled goods, which are displaced with
respect to the center line of the delivery conveyor, cannot be positioned
precisely without correcting the tipping tray. This problem can be solved
by various measures. As a precise placing of the parceled goods on the
center line of the delivery conveyor, which would solve the problem,
cannot be achieved without encountering other disadvantages, in the
solutions offered by EP A 0 305 755, EP A 0 343 613 or EP A 0 619 248, the
time, at which a parcel reaches the acceptance conveyor, is selected as a
function of its position which is relative to the center line of the
delivery conveyor. In EP A 0 305 755, a counting device is controlled by
two light barriers intersecting at a specific angle, which, as a function
of the position of the parceled goods, transmits the counting result as
the parceled goods pass through the light barrier, as a result of which is
activated a proportional delay of the otherwise static channeling process.
In EP A 0 343 613, instead of delaying the start of the channeling
process, this delay is achieved by using two different speeds (v.sub.o
/.sqroot.2) or (v.sub.o *.sqroot.2) which temporally are set as a function
of the position of the parceled goods along a light barrier which is
directed parallel to the acceptance conveyor or as a function of the
position of the parceled goods relative to the center line of the delivery
conveyor. Instead of a starting time depending on the position of the
parcel, in the second example, the time for switching between varying
speeds is selected as a function of the position of the parcel, in order
to achieve the required delay. The second speed (v.sub.o *.sqroot.2) is
the speed with which parceled goods are channeled on the acceptance
conveyor (channeling speed). The first speed (v.sub.o /.sqroot.2), which
is selected to delay the parceled goods, therefore, always is lower than
the channeling speed. With the known devices from EP A 0 305 755 and EP A
0 343 613, a delay is effected which is selected as a function of the
lateral position of the parcel located on the delivery conveyor. This
delay, which is effected independent from the position of the tipping
trays provided on the acceptance conveyor, therefore, serves exclusively
to balance the lateral displacement of parceled goods on the delivery
conveyor.
In EP A 0 619 248, prior to accelerating the light barrier, which runs
vertically along the acceptance conveyor, the parceled goods are stopped
until the channeling process is initiated. The resulting displacement of
the parceled goods in the direction of conveyance as a function of the
lateral displacement on the delivery conveyor effects a uniform
acceleration of each parcel at the acceptance conveyor.
The devices according to EP A2 0 305 755 (see page 5, lines 37-42), EP A2 0
343 613 (column 4, lines 41-57) and EP A1 0 619 248 (column 4, lines
13-25) further have in common that the parceled goods are stopped for the
time during which the host computer determines the distance to the next
empty tipping tray. This causes interruptions within the channeling
processes which clearly reduce the processing speed of parceled goods.
Delays also result from the fact that after stopping the parceled goods
must accelerate to regain their channeling speed. As a result, it may
happen that because of the stopping and acceleration process, an empty
tipping tray may be missed. A stopping process may under certain
circumstances only be avoided if an empty tipping tray is located at a
suitable distance from the transfer point.
SUMMARY OF THE INVENTION
The present invention provides a process and apparatus in which parceled
goods can be channeled in basic cycles from a delivery conveyor to an
acceptance conveyor. In particular, idle time is to be avoided when
channeling parceled goods, unless empty containers or tipping trays
already move synchronously on the acceptance conveyor.
The present invention provides a process that includes measuring a length
of a parcel to be channeled, determining a length of time t2 utilized in
measuring the length of the parcel, and determining a momentary parcel
speed; a speed of the channeling conveyor to which the parcel will be
transferred; a distance on the call-up conveyor on which acceleration of
the parcel occurs prior to a transfer of the parcel to the channeling
conveyor; and a position of a next free space on the acceptance conveyor.
The process also includes synchronizing movement of the parcel to the next
free space by one of (a) accelerating and decelerating and (b)
decelerating and accelerating the parcel on the call-up conveyor at a
constant acceleration a, and without intermediate stopping of the call-up
conveyor, transferring the parcel from the call-up conveyor to the
channeling conveyor, and synchronously transferring the parcel to the next
free space on the acceptance conveyor.
The present invention also provides an apparatus that includes a measuring
device to measure a length of a parcel to be transferred from the delivery
conveyor to the acceptance conveyor, wherein the measurement of the length
occurs in a time t2, a control device provided for determining a momentary
speed of parcel; a speed of the channeling conveyor to which the parcel
will be transferred; a distance on the call-up conveyor on which
acceleration of the parcel occurs prior to a transfer to the channeling
conveyor; and a position of a next empty space on the acceptance conveyor.
The control device also is provided to adjust one of (a) an acceleration
and deceleration and (b) a deceleration and acceleration of the parcel on
the call-up conveyor, without intermediate stopping of the call-up
conveyor, to synchronize the movement of the parcel to the next empty
space on the acceptance conveyor.
The inventive process and the device enable a reduction in interfering idle
times, while channeling parceled goods of similar or different sizes. The
idle times reducing the processing of parceled goods can thus occur only
if the acceptance conveyor does not make available empty tipping trays
over a long period. Further, a targeted acceleration of the channeling
processing, which is contingent upon the position of the tipping trays to
be loaded and the size of the parceled goods, is achieved which enables
synchronization of parceled goods with empty tipping trays with respect to
the transfer time, which could no longer be reached with the known method
and thus would continue to be conveyed unused on the acceptance conveyor.
Instead of the static channeling process, a process is implemented which
dynamically balances the parceled goods and the position of the tipping
trays, which allows channeling the parceled goods within the shortest
possible time. In contrast to known devices, the device provided according
the inventive method can be implemented practically without additional
expenditure.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in detail by means of a drawing. Of the
drawings:
FIG. 1 shows a central acceptance conveyor on which parceled goods are
channeled via a delivery conveyor provided with a call-up conveyor, and
FIG. 2 shows a device according to FIG. 1 with a delivery conveyor provided
with two call-up conveyors.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
FIG. 1 shows a delivery conveyor AGF comprised of a buffer conveyor PB, a
call-up conveyor AB and a channeling conveyor EB, through which parceled
goods FS are channeled on an acceptance conveyor ANF. Also shown are a
channeling process for a parcel FS, which is controlled by a control unit
STI, and the speed variation with which the parcel FS is conveyed through
the delivery conveyor AGF. Following the channeling process, the parcel FS
is to be placed precisely in a single or multiple container or tipping
tray which is conveyed by the acceptance conveyor ANF. If the parcel FS is
made available in due time, it will preferably be positioned at the front
edge of the tipping tray (front edge of the parcel FS at the front edge of
the tipping tray KS), in order to empty the delivery conveyor AGF as soon
as possible and to ready said container for channeling a further parcel
FS. However, if the parcel is passed on relatively late by the buffer
conveyer PB to the call-up conveyor AB, the positioning preferably takes
place at the rear edge of the tipping tray (rear edge of the parcel FS at
the rear edge of the tipping tray KS). In order to simplify the control
processes, the parceled goods FS can be respectively positioned in the
center of the tipping tray KS. The channeling processes with corresponding
positioning of the parceled goods FS, can be performed in that the
parceled goods FS are readied in the area of the call-up conveyor AB as is
the case in the prior art of a stopping line, and they can be accelerated
to the channeling speed after the tipping tray KS has appeared at a
specific point. This will result in idle times which will be avoided with
the inventive channeling method.
According to the invention, without stopping the parcel FS, a check is
performed at a specific time (t2), in order to determine for how long the
parcel FS is to be accelerated along a calculated distance of
synchronization I.sub.syn on the call-up conveyor AB, so that the next
empty tipping tray KS can still be reached. Further, it is preferably
checked whether the parcel FS can still be positioned at the front edge,
in the center or only at the rear edge of the tipping tray KS. The
acceleration process takes place on the call-up conveyor AB after the
length has been measured. The speed variation of the call-up conveyor AB,
as shown in FIGS. 1 and 2 in a diagram, is consistent with the speed of
the conveyed parcel FS, so long said parcel is located on the call-up
conveyor AB.
In order to perform the necessary calculations, the information i-ks with
respect to the existing empty tipping trays, information t-anf, tl-anf
(cycling rate and cycle length) with respect to the speed VANF of the
acceptance conveyor ANF, information .alpha. with respect to the angle
encompassed by the supply conveyor AGF and the acceptance conveyor ANF, as
well as information s-is1, s-is2, s-is3 with respect to the position of
the parcel FS to be channeled, is to be transmitted to the control unit
ST1. The information s-is1, s-is2, s-is3 concerning the position of the
parcel FS to be channeled is to be transmitted by three light barriers
LS1, LS2 and LS3 to the control unit ST1. The calculations described in
the following refer to the position of a parcel FS at the light barrier
LS2. The first light barrier LS1 is positioned at the end of the buffer
conveyor PB and so located orthogonally to the running direction of said
conveyor that the parceled good FS, which are stopped at the light barrier
LS1, at the beginning of the channeling process can be accelerated to the
speed v.sub.UE of the call-up conveyor AB prior to being transferred to
the call-up conveyor. The second light barrier LS2 which is provided to
measure the length of the parceled goods FS and are provided as a starting
point for the acceleration process, is orthogonally arranged at the
acceptance conveyor ANF, in order to compensate, as described in the
above, deviations of the parceled goods FS from the center line of the
call-up conveyor or the delivery conveyor AGF.
The calculations described in the following, therefore, can be performed
irrespective of lateral displacement of a parcel FS on the delivery
conveyor AGF.
The control unit ST1 (also applies to FIG. 2, ST2) is provided with a
counting device for calculating and controlling the delivery conveyor AGF
or the corresponding conveyors (buffer conveyor PB, call-up conveyor AB
(AB1, AB2), while the channeling conveyor EB preferably runs at a constant
channeling speed v.sub.ES). During this process, the control unit ST1
transmits control signals c-pb, c-ab (c-ab1, c-ab2) to the delivery
conveyor AGF.
In the following, the path I.sub.syn on the call-up conveyor AB is
determined which is available for synchronization of the parceled goods
FS.
The length of the parceled goods FS is measured in that the time is
measured during which the parcel FS passes through the light barrier LS2
at the take over speed v.sub.UE. (The edges pass through diagonally to
each other.) FIG. 1 shows that after measuring the length, the parcel FS
conveyed on the left edge of the delivery conveyor AGF already traveled a
distance b.sub.AB * tan .alpha. on the call-up conveyor AB (b.sub.AB
=width of the call-up conveyor AB). This section can no longer be used for
synchronizing the parcel FS with a tipping tray KS, which is to be
performed on the call-up conveyor AB.
Further, the section I.sub.syn available for synchronization is reduced by
the section I.sub.acc through which the parcel FS must pass (during the
time t.sub.acc). Due to the difference in speed v.sub.UE and v.sub.ES, as
well as a given, preferably constant selected acceleration a, the distance
of acceleration I.sub.acc can be calculated:
I.sub.acc =(v.sub.ES.sup.2 -v.sub.UE.sup.2)/2*a
The time t.sub.acc required for the acceleration process is:
t.sub.acc =(v.sub.ES -v.sub.UE)/a
In addition, the distance of synchronization is reduced by approximately
the length I'.sub.FS of the measured parcel FS, as said parcel is to be
conveyed at the channeling speed v.sub.ES when reaching the channeling
conveyor EB.
Upon closer consideration, it can be determined that the measured length
I'.sub.FS of the parcel FS can be reduced by the value b.sub.FS *tan
.alpha. (b.sub.FS is the width of the parcel FS), as the measured value
with similar length of the parcel increases in proportion to the width
b.sub.FS of the parcel FS in the direction of conveyance. With the given
minimum width b.sub.FS of the parcel FS, the measured length I'.sub.FS
thus can be optimized in a first approximation. In order to create a
safety margin, this correction value, however, is not deducted. As an
alternative, the length of the parcel can also be measured by means of the
first light barrier LS1 which is located orthogonally to the buffer
conveyor PB. This would result in measuring I'.sub.FS of the parceled
goods FS independent of their width b.sub.FS.
The length I.sub.AB of the call-up conveyor AB, reduced by the path
(b.sub.AB *tan .alpha.), the distance of acceleration I.sub.acc and the
length I'.sub.FS of the parcel FS thus results in the length I.sub.syn of
the distance of synchronization:
I.sub.syn =I.sub.AB -b.sub.AB *tan .alpha.-I.sub.acc -I'.sub.FS
The object of the synchronization process is that, in terms of the
direction of the acceptance conveyor ANF, upon completion of
synchronization (time t5) a reserved tipping tray KS is at the same level
and moves at the same speed V.sub.ANF. The channeling V.sub.ES of the
delivery conveyor AGF thus is selected as a function as a function of the
angle .alpha. which is encompassed by the conveying devices ANF and AGF:
V.sub.ES =V.sub.ANF /cos .alpha.
During the calculation of the synchronization process it must also be taken
into consideration that the tipping tray KS was conveyed by the distance
S.sub.K, while the parcel FS was accelerated within the section I.sub.acc
during the time t.sub.acc :
S.sub.K =V.sub.ANF *t.sub.acc
Within the distance of synchronization I.sub.syn, the parcel FS must
additionally make up the difference between the distances or differential
distances S.sub.diff which the tipping tray KS and the parcel FS traveled
within the time t.sub.acc in the direction of the acceptance conveyor ANF:
S.sub.diff =S.sub.K -cos .alpha.*I.sub.acc
The time t.sub.syn (time t3 to t5) available for synchronization can be
calculated by establishing how long it takes for a tipping tray KS to
travel the length I.sub.syn corresponding to the distance of
synchronization along the acceptance conveyor ANF:
t.sub.syn =cos .alpha.I.sub.syn /V.sub.ANF
The distance at which a parcel FS can catch up with a tipping tray at a
constant acceleration within the time t.sup.syn, is calculated in that the
time t.sub.syn is subdivided into equally long phases of positive and
negative acceleration (times t3 to t4 or t4 to t5) (acceleration of
channeling speed v.sub.ES to maximum speed at the transfer point (Phase 1)
and back to the channeling speed v.sub.ES (Phase 2). For this reason the
caught-up distance for the first phase is calculated and multiplied by
two. The distance S.sub.auf caught up in the time t.sub.syn is converted
in the direction of the acceptance conveyor ANF and therefore is:
S.sub.auf =cos .alpha.*a*(t.sub.syn /2).sup.2
After measuring the length and prior to starting the acceleration phase, a
parcel FS, however, can only completely catch up with a tipping tray KS in
terms of distance S.sub.tot within the distance of acceleration I.sub.acc
and the distance of synchronization I.sub.syn :
S.sub.tot =S.sub.auf -S.sub.diff
Due to a variation of the length I.sub.syn of the distance of
synchronization or the time of synchronization t.sub.syn, the catching up
distance or the distance S.sub.tot to be caught up can be set randomly.
With a constant acceleration a over the entire length I.sub.syn of the
distance of synchronization, the distance S.sub.tot =S.sub.max can be
caught up.
In FIG. 2, the tipping tray KS1 moves ahead of a parcel FS by the maximum
distance S.sub.max and, therefore, can still be reached at a constant
acceleration a (positioning of the rear edge). FIG. 2 further shows the
speed variation vIKS1 of the call-up conveyor AB1; AB2 or the parcel FS
during the channeling process towards the tipping tray KS1. A tipping tray
KS, which runs farther ahead than the distance S.sub.max, can no longer be
reached by the parcel, even with a constant acceleration a. FIG. 2 also
shows the speed variation vI.sub.KSO of the parcel FS in the course of
channeling on a tipping tray KSO which runs ahead less than the distance
S.sub.max. In order to catch up this tipping tray KSO, the parcel FS is
accelerated only during a short time t'.sub.SYN which is selected in such
a way that the caught-up distance S.sub.tot :
S.sub.tot =cos .alpha.*a*(t'.sub.SYN /2).sup.2 -S.sub.diff
is consistent with the distance between the tipping tray KSO and the parcel
FS (again in reference to the direction of the acceptance conveyor ANF).
Due to the variation of the time of synchronization t'.sub.SYN, the
acceleration a can be maintained constant, thus enabling a simple
technical implementation. The acceleration of the parcel thus starts at
the time t2 and ends at the time t5. The acceleration phase, however, may
also start at a later time tx if said phase can be completed by time t5.
The first variant is preferred if, when using several call-up conveyors
AB1, AB2, the first call-up conveyor AB1 is to be cleared as soon as
possible. At the same time, one must take into consideration that the
maximum time of synchronization t.sub.syn depends on the length I.sub.FS
of the parceled goods FS and thus changes in any case from one channeling
process to another. In principle, however, devices with variable
acceleration may be used.
In the event that a parcel FS must wait for a longer period on a tipping
tray KS, it is advantageous if the channeling process is not interrupted.
In FIG. 2, the tipping tray KS follows a parcel FS and can only be reached
(preferable positioning at the front edge) if the parcel FS is delayed.
FIG. 2 shows the corresponding speed variation vI.sub.KS2 of the call-up
conveyors AB1, AB2, or the parcel FS as they are being channeled on to the
tipping tray KS2.
By using two call-up conveyors AB1, AB2, the channeling process can be made
more flexible; for example, the first call-up conveyor AB1 can be set to
transfer speed v.sub.UE if the parcel FS is still conveyed on the second
call-up conveyor AB2 at channeling speed v.sub.ES. For this purpose, light
barriers LS3 or LS3, LS4 are preferably provided which transmit to the
control unit ST1, ST2 a corresponding message, as soon as the parcel FS
has left the respective conveyor AB or AB1 or AB2.
In the above sections, care was taken for the purpose of synchronization
that the distance between the parcel FS and a free tipping tray KS is
caught up and balanced. This, however, can also be achieved by determining
how long it takes until the tipping tray KS arrives at the point at which
the synchronization process is concluded (FIG. 2, time t5). This time
t.sub.KS thus is exactly consistent with the time which passes between
times t2 and t5:
t.sub.KS =t.sub.acc +t.sub.syn
After the length has been measured, the parcel FS to be channeled,
therefore, is to be accelerated and decelerated until, after the speed
variation t.sub.KS =the distances t.sub.acc +t.sub.syn and the channeling
conveyor is reached as a result of which the tipping tray KS is
synchronized.
In EP A 0 305 755, a counting device is controlled by means of two light
barriers intersecting at a specific angle, which produces a count as a
function of the position of the parceled goods when passing through the
light barriers, said result being effected by a proportional delay
t.sub.DEL of the otherwise static channeling process. The light barrier
(LS2) provided at the beginning of the call-up conveyor (AB; AB1) may thus
also be provided vertically to the delivery conveyor (AGF) when using this
measuring device. In this case, the distance of synchronization has the
length I.sub.syn :
I.sub.syn =I.sub.AB -I.sub.ACC -I'.sub.FS
The delay t.sub.DEL is taken into consideration by a corresponding
shortening of the time of synchronization t.sub.syn. For the sake of
simplicity, it can be assumed that the next free tipping tray KS is
provided with a temporal distance t.sub.KS +t.sub.DEL. The time of
synchronization t.sub.syn, therefore, must be calculated as follows:
t.sub.syn =t.sub.KS -t.sub.acc +t.sub.DEL
The inventive method thus can also be used with known devices for
channeling parceled goods.
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